The following is based on the Motu Propio of Pope Pius XII, March 19, 1957:
1. Priests (before Mass) and faithful (before Holy Communion) – whether it is the morning, afternoon, evening or Midnight Mass – must abstain for three hours from solid foods and alcoholic beverages, and for one hour from non-alcoholic beverages. Water does not break the fast.
2. The infirm, even if not bedridden, may take non-alcoholic beverages and that which is really and proper medicine, either in liquid or solid form, before Mass or Holy Communion without any time limit.
EXHORTATION OF POPE PIUS XII
His Holiness, Pope Pius XII, earnestly exhorts priests and faithful who are able to do so to observe the old and venerable form of the Eucharistic fast (from foods and liquids from midnight) before Holy Communion.
All those who will make use of these concessions must compensate for the good received by becoming shining examples of a Christian life and principally with works of penance and charity.
For any questions or clarifications, please discuss with the priest.